Store bought cupcake mix for those that don't make theirs from scratch will work. Core out the cupcakes and from there, pipe in the buttercream and cover the top of the cake so the marshmallows have a secure area to rest on. Next and this is for the parent or adult present, take a small torch and set the marshmallows ablaze. Extinguish and cover with graham crackers that have been crushed. Serve immediately.